DOKK / manpages / debian 11 / firejail / firejail-profile.5.en
FIREJAIL-PROFILE(5) firejail profiles man page FIREJAIL-PROFILE(5)

profile - Security profile file syntax for Firejail


firejail --profile=profile_name

Several command line options can be passed to the program using profile files. Firejail chooses the profile file as follows:

1. If a profile file is provided by the user with --profile option, the profile file is loaded. If a profile name is given, it is searched for first in the ~/.config/firejail directory and if not found then in /etc/firejail directory. Profile names do not include the .profile suffix. Example:

$ firejail --profile=/home/netblue/icecat.profile icecat
Reading profile /home/netblue/icecat.profile
[...]

$ firejail --profile=icecat icecat-wrapper.sh
Reading profile /etc/firejail/icecat.profile
[...]

2. If a profile file with the same name as the application is present in ~/.config/firejail directory or in /etc/firejail, the profile is loaded. ~/.config/firejail takes precedence over /etc/firejail. Example:

$ firejail icecat
Command name #icecat#
Found icecat profile in /home/netblue/.config/firejail directory
Reading profile /home/netblue/.config/firejail/icecat.profile
[...]

3. Use a default.profile file if the sandbox is started by a regular user, or a server.profile file if the sandbox is started by root. Firejail looks for these files in ~/.config/firejail directory, followed by /etc/firejail directory. To disable default profile loading, use --noprofile command option. Example:

$ firejail
Reading profile /etc/firejail/default.profile
Parent pid 8553, child pid 8554
Child process initialized
[...]

$ firejail --noprofile
Parent pid 8553, child pid 8554
Child process initialized
[...]

In /usr/share/doc/firejail there are two templates to write new profiles.

profile.template - for regular profiles
redirect_alias-profile.template - for aliasing/redirecting profiles

Scripting commands:

File and directory names containing spaces are supported. The space character ' ' should not be escaped.

Example: "blacklist ~/My Virtual Machines"

# this is a comment

?CONDITIONAL: profile line
Conditionally add profile line.

Example: "?HAS_APPIMAGE: whitelist ${HOME}/special/appimage/dir"

This example will load the whitelist profile line only if the --appimage option has been specified on the command line.

Currently the only conditionals supported this way are HAS_APPIMAGE, HAS_NET, HAS_NODBUS, HAS_NOSOUND and HAS_X11. The conditionals BROWSER_DISABLE_U2F and BROWSER_ALLOW_DRM can be enabled or disabled globally in Firejail's configuration file.

The profile line may be any profile line that you would normally use in a profile except for "quiet" and "include" lines.

Include other.profile file.

Example: "include /etc/firejail/disable-common.inc"

The file name can be prefixed with a macro such as ${HOME} or ${CFG}. ${HOME} is expanded as user home directory, and ${CFG} is expanded as Firejail system configuration directory - in most cases /etc/firejail or /usr/local/etc/firejail.

Example: "include ${HOME}/myprofiles/profile1" will load "~/myprofiles/profile1" file.

Example: "include ${CFG}/firefox.profile" will load "/etc/firejail/firefox.profile" file.

The file name may also be just the name without the leading directory components. In this case, first the user config directory (${HOME}/.config/firejail) is searched for the file name and if not found then the system configuration directory is search for the file name. Note: Unlike the --profile option which takes a profile name without the '.profile' suffix, include must be given the full file name.

Example: "include firefox.profile" will load "${HOME}/.config/firejail/firefox.profile" file and if it does not exist "${CFG}/firefox.profile" will be loaded.

System configuration files in ${CFG} are overwritten during software installation. Persistent configuration at system level is handled in ".local" files. For every profile file in ${CFG} directory, the user can create a corresponding .local file storing modifications to the persistent configuration. Persistent .local files are included at the start of regular profile files.

If the file name matches file_name, the file will not be blacklisted in any blacklist commands that follow.

Example: "noblacklist ${HOME}/.mozilla"

If the file name matches file_name, the file will not be whitelisted in any whitelist commands that follow.

Example: "nowhitelist ~/.config"

Ignore command.

Example: "ignore seccomp"
Example: "ignore net eth0"

Disable Firejail's output. This should be the first uncommented command in the profile file.

Example: "quiet"

These profile entries define a chroot filesystem built on top of the existing host filesystem. Each line describes a file/directory that is inaccessible (blacklist), a read-only file or directory (read-only), a tmpfs mounted on top of an existing directory (tmpfs), or mount-bind a directory or file on top of another directory or file (bind). Use private to set private mode. File globbing is supported, and PATH and HOME directories are searched, see the firejail FILE GLOBBING section for more details. Examples:

Blacklist directory or file. Examples:

blacklist /usr/bin
blacklist /usr/bin/gcc*
blacklist ${PATH}/ifconfig
blacklist ${HOME}/.ssh

When --tracelog flag is set, blacklisting generates syslog messages if the sandbox tries to access the file or directory. blacklist-nolog command disables syslog messages for this particular file or directory. Examples:

blacklist-nolog /usr/bin
blacklist-nolog /usr/bin/gcc*

Mount-bind directory1 on top of directory2. This option is only available when running as root.
Mount-bind file1 on top of file2. This option is only available when running as root.
Disable /mnt, /media, /run/mount and /run/media access.
/dev/shm directory is untouched (even with private-dev).
/var/tmp directory is untouched.
Create a directory in user home, under /tmp, or under /run/user/<UID> before the sandbox is started. The directory is created if it doesn't already exist.

Use this command for whitelisted directories you need to preserve when the sandbox is closed. Without it, the application will create the directory, and the directory will be deleted when the sandbox is closed. Subdirectories are recursively created. Example from firefox profile:

mkdir ~/.mozilla
whitelist ~/.mozilla
mkdir ~/.cache/mozilla/firefox
whitelist ~/.cache/mozilla/firefox

For files in /run/user/<PID> use ${RUNUSER} macro:

mkdir ${RUNUSER}/firejail-testing

Similar to mkdir, this command creates an empty file in user home, or /tmp, or under /run/user/<UID> before the sandbox is started. The file is created if it doesn't already exist.
Remount the file or the directory noexec, nodev and nosuid.
Mount new /root and /home/user directories in temporary filesystems. All modifications are discarded when the sandbox is closed.
private directory
Use directory as user home.
Build a new /bin in a temporary filesystem, and copy the programs in the list. The files in the list must be expressed as relative to the /bin, /sbin, /usr/bin, /usr/sbin, or /usr/local/bin directories. The same directory is also bind-mounted over /sbin, /usr/bin and /usr/sbin.
Mount an empty temporary filesystem on top of the .cache directory in user home. All modifications are discarded when the sandbox is closed.
Set working directory inside jail to the home directory, and failing that, the root directory.
private-cwd directory
Set working directory inside the jail.
Create a new /dev directory. Only disc, dri, dvb, hidraw, null, full, zero, tty, pts, ptmx, random, snd, urandom, video, log, shm and usb devices are available. Use the options no3d, nodvd, nosound, notv, nou2f and novideo for additional restrictions.

Build a new /etc in a temporary filesystem, and copy the files and directories in the list. The files and directories in the list must be expressed as relative to the /etc directory. All modifications are discarded when the sandbox is closed.
Build a new user home in a temporary filesystem, and copy the files and directories in the list in the new home. The files and directories in the list must be expressed as relative to the current user's home directory. All modifications are discarded when the sandbox is closed.
Build a new /lib directory and bring in the libraries required by the application to run. The files and directories in the list must be expressed as relative to the /lib directory. This feature is still under development, see man 1 firejail for some examples.
Build a new /opt in a temporary filesystem, and copy the files and directories in the list. The files and directories in the list must be expressed as relative to the /opt directory. All modifications are discarded when the sandbox is closed.
Build a new /srv in a temporary filesystem, and copy the files and directories in the list. The files and directories in the list must be expressed as relative to the /srv directory. All modifications are discarded when the sandbox is closed.
Mount an empty temporary filesystem on top of /tmp directory whitelisting /tmp/.X11-unix.
Make directory or file read-only.
Make directory or file read-write.
Mount an empty tmpfs filesystem on top of directory. This option is available only when running the sandbox as root.
Blacklist violations logged to syslog.
Whitelist directory or file. A temporary file system is mounted on the top directory, and the whitelisted files are mount-binded inside. Modifications to whitelisted files are persistent, everything else is discarded when the sandbox is closed. The top directory could be user home, /dev, /etc, /media, /mnt, /opt, /srv, /sys/module, /usr/share, /var, and /tmp.

Symbolic link handling: with the exception of user home, both the link and the real file should be in the same top directory. For user home, both the link and the real file should be owned by the user.

Mount /etc directory read-write.
Disable the default blacklisting of run/user/$UID/systemd and /run/user/$UID/gnupg.
Mount /var directory read-write.
Use the real /var/log directory, not a clone. By default, a tmpfs is mounted on top of /var/log directory, and a skeleton filesystem is created based on the original /var/log.

The following security filters are currently implemented:

Allow tools such as strace and gdb inside the sandbox by whitelisting system calls ptrace and process_vm_readv.
Enable AppArmor confinement.
Enable default Linux capabilities filter.
Blacklist given Linux capabilities.
Blacklist all Linux capabilities.
Whitelist given Linux capabilities.
Install a seccomp filter to block attempts to create memory mappings that are both writable and executable, to change mappings to be executable or to create executable shared memory.
Sets the NO_NEW_PRIVS prctl. This ensures that child processes cannot acquire new privileges using execve(2); in particular, this means that calling a suid binary (or one with file capabilities) does not result in an increase of privilege.
Use this command to enable an user namespace. The namespace has only one user, the current user. There is no root account (uid 0) defined in the namespace.
Enable protocol filter. The filter is based on seccomp and checks the first argument to socket system call. Recognized values: unix, inet, inet6, netlink, packet and bluetooth.
Enable seccomp filter and blacklist the syscalls in the default list. See man 1 firejail for more details.
Enable seccomp filter and blacklist the syscalls in the default list for 32 bit system calls on a 64 bit architecture system.
seccomp syscall,syscall,syscall
Enable seccomp filter and blacklist the system calls in the list on top of default seccomp filter.
seccomp.32 syscall,syscall,syscall
Enable seccomp filter and blacklist the system calls in the list on top of default seccomp filter for 32 bit system calls on a 64 bit architecture system.
Enable seccomp filter and filter system call architectures so that only the native architecture is allowed.
Enable seccomp filter and blacklist the system calls in the list.
Enable seccomp filter and blacklist the system calls in the list for 32 bit system calls on a 64 bit architecture system.
Enable seccomp filter and whitelist the system calls in the list.
Enable seccomp filter and whitelist the system calls in the list for 32 bit system calls on a 64 bit architecture system.
Return a different error instead of EPERM to the process, kill it when an attempt is made to call a blocked system call, or allow but log the attempt.
Enable X11 sandboxing.
x11 none
Blacklist /tmp/.X11-unix directory, ${HOME}/.Xauthority and file specified in ${XAUTHORITY} environment variable. Remove DISPLAY and XAUTHORITY environment variables. Stop with error message if X11 abstract socket will be accessible in jail.
x11 xephyr
Enable X11 sandboxing with Xephyr server.
x11 xorg
Enable X11 sandboxing with X11 security extension.
x11 xpra
Enable X11 sandboxing with Xpra server.
x11 xvfb
Enable X11 sandboxing with Xvfb server.
Set screen size for x11 xephyr. This command should be included in the profile file before x11 xephyr command.

Example:

xephyr-screen 640x480
x11 xephyr

Access to the session and system DBus UNIX sockets can be allowed, filtered or disabled. To disable the abstract sockets (and force applications to use the filtered UNIX socket) you would need to request a new network namespace using --net command. Another option is to remove unix from the --protocol set.

Filtering requires installing the xdg-dbus-proxy utility. Filter rules can be specified for well-known DBus names, but they are also propagated to the owning unique name, too. The permissions are "sticky" and are kept even if the corresponding well-known name is released (however, applications rarely release well-known names in practice). Names may have a .* suffix to match all names underneath them, including themselves (e.g. "foo.bar.*" matches "foo.bar", "foo.bar.baz" and "foo.bar.baz.quux", but not "foobar"). For more information, see xdg-dbus-proxy(1).

Examples:

Enable filtered access to the system DBus. Filters can be specified with the dbus-system.talk and dbus-system.own commands.
Disable access to the system DBus. Once access is disabled, it cannot be relaxed to filtering.
Allow the application to own the name org.gnome.ghex and all names underneath in on the system DBus.
Allow the application to talk to the name org.freedesktop.Notifications on the system DBus.
Allow the application to see but not talk to the name org.freedesktop.Notifications on the system DBus.
Allow the application to call methods of the interface org.freedesktop.Notifications of the object exposed at the path /org/freedesktop/Notifications by the client owning the bus name org.freedesktop.Notifications on the system DBus.
Allow the application to receive broadcast signals from the the interface org.freedesktop.Notifications of the object exposed at the path /org/freedesktop/Notifications by the client owning the bus name org.freedesktop.Notifications on the system DBus.
Enable filtered access to the session DBus. Filters can be specified with the dbus-user.talk and dbus-user.own commands.
Disable access to the session DBus. Once access is disabled, it cannot be relaxed to filtering.
Allow the application to own the name org.gnome.ghex and all names underneath in on the session DBus.
Allow the application to talk to the name org.freedesktop.Notifications on the session DBus.
Allow the application to see but not talk to the name org.freedesktop.Notifications on the session DBus.
Allow the application to call methods of the interface org.freedesktop.Notifications of the object exposed at the path /org/freedesktop/Notifications by the client owning the bus name org.freedesktop.Notifications on the session DBus.
Allow the application to receive broadcast signals from the the interface org.freedesktop.Notifications of the object exposed at the path /org/freedesktop/Notifications by the client owning the bus name org.freedesktop.Notifications on the session DBus.
Disable D-Bus access (both system and session buses). Equivalent to dbus-system none and dbus-user none.

Individual filters can be overridden via the --ignore command. Supposing a profile has
[...]
dbus-user filter
dbus-user.own org.mozilla.firefox.*
dbus-user.talk org.freedesktop.Notifications
dbus-system none
[...]

and the user wants to disable notifications, this can be achieved by putting the below in a local override file:
[...]
ignore dbus-user.talk org.freedesktop.Notifications
[...]

These profile entries define the limits on system resources (rlimits) for the processes inside the sandbox. The limits can be modified inside the sandbox using the regular ulimit command. cpu command configures the CPU cores available, and cgroup command place the sandbox in an existing control group.

Examples:

The sandbox is placed in g1 control group.
Use only CPU cores 0, 1 and 2.
Set a nice value of -5 to all processes running inside the sandbox.
Set the maximum size of the process's virtual memory to 123456789012 bytes.
Set the maximum CPU time in seconds.
Set the maximum file size that can be created by a process to 1024 bytes.
Set the maximum number of processes that can be created for the real user ID of the calling process to 1000.
Set the maximum number of files that can be opened by a process to 500.
Set the maximum number of processes that can be created for the real user ID of the calling process to 200.
Kill the sandbox automatically after the time has elapsed. The time is specified in hours/minutes/seconds format.

All user home directories are visible inside the sandbox. By default, only current user home directory is visible.

Set environment variable. Examples:

env LD_LIBRARY_PATH=/opt/test/lib
env CFLAGS="-W -Wall -Werror"

Enable IPC namespace.
Set sandbox name. Example:

name browser

Disable 3D hardware acceleration.
Disable automatic ~/.config/pulse init, for complex setups such as remote pulse servers or non-standard socket paths.
Disable DVD and audio CD devices.
Disable supplementary user groups
Disable sound system.
Disable DVB (Digital Video Broadcasting) TV devices.
Disable U2F devices.
Disable video devices.
Run the program directly, without a shell.

Networking features available in profile files.

Use this address as default gateway in the new network namespace.

Set a DNS server for the sandbox. Up to three DNS servers can be defined.

Set a hostname for the sandbox.

Use file as /etc/hosts.

Assign IP addresses to the last network interface defined by a net command. A default gateway is assigned by default.

Example:
net eth0
ip 10.10.20.56

No IP address and no default gateway are configured for the last interface defined by a net command. Use this option in case you intend to start an external DHCP client in the sandbox.

Example:
net eth0
ip none

Acquire an IP address and default gateway for the last interface defined by a net command, as well as set the DNS servers according to the DHCP response. This command requires the ISC dhclient DHCP client to be installed and will start it automatically inside the sandbox.

Example:
net br0
ip dhcp

This command should not be used in conjunction with the dns command if the DHCP server is set to configure DNS servers for the clients, because the manually specified DNS servers will be overwritten.

The DHCP client will NOT release the DHCP lease when the sandbox terminates. If your DHCP server requires leases to be explicitly released, consider running a DHCP client and releasing the lease manually in conjunction with the net none command.

Assign IPv6 addresses to the last network interface defined by a net command.

Example:
net eth0
ip6 2001:0db8:0:f101::1/64

Acquire an IPv6 address and default gateway for the last interface defined by a net command, as well as set the DNS servers according to the DHCP response. This command requires the ISC dhclient DHCP client to be installed and will start it automatically inside the sandbox.

Example:
net br0
ip6 dhcp

This command should not be used in conjunction with the dns command if the DHCP server is set to configure DNS servers for the clients, because the manually specified DNS servers will be overwritten.

The DHCP client will NOT release the DHCP lease when the sandbox terminates. If your DHCP server requires leases to be explicitly released, consider running a DHCP client and releasing the lease manually.

Assign an IP address in the provided range to the last network interface defined by a net command. A default gateway is assigned by default.

Example:

net eth0
iprange 192.168.1.150,192.168.1.160

Assign MAC addresses to the last network interface defined by a net command.

Spoof id number in /etc/machine-id file - a new random id is generated inside the sandbox.

Assign a MTU value to the last network interface defined by a net command.

Enable a new network namespace and connect it to this bridge interface. Unless specified with option --ip and --defaultgw, an IP address and a default gateway will be assigned automatically to the sandbox. The IP address is verified using ARP before assignment. The address configured as default gateway is the bridge device IP address. Up to four --net bridge devices can be defined. Mixing bridge and macvlan devices is allowed.

Enable a new network namespace and connect it to this ethernet interface using the standard Linux macvlan or ipvlan driver. Unless specified with option --ip and --defaultgw, an IP address and a default gateway will be assigned automatically to the sandbox. The IP address is verified using ARP before assignment. The address configured as default gateway is the default gateway of the host. Up to four --net devices can be defined. Mixing bridge and macvlan devices is allowed.

Enable a new, unconnected network namespace. The only interface available in the new namespace is a new loopback interface (lo). Use this option to deny network access to programs that don't really need network access.

Enable a new network namespace and connect it to this ethernet tap interface using the standard Linux macvlan driver. If the tap interface is not configured, the sandbox will not try to configure the interface inside the sandbox. Please use ip, netmask and defaultgw to specify the configuration.

If a new network namespace is created, enabled default network filter.

netfilter filename
If a new network namespace is created, enabled the network filter in filename.

Use this option when you want to assign an IP address in a new namespace and the parent interface specified by --net is not configured. An IP address and a default gateway address also have to be added.

Run the program in a named, persistent network namespace. These can be created and configured using "ip netns".

Use this name for the interface connected to the bridge for --net=bridge_interface commands, instead of the default one.

Always exit firejail with the first child's exit status. The default behavior is to use the exit status of the final child to exit, which can be nondeterministic.

Join the sandbox identified by name or start a new one. Same as "firejail --join=sandboxname" command if sandbox with specified name exists, otherwise same as "name sandboxname".

/etc/firejail/filename.profile, $HOME/.config/firejail/filename.profile

Firejail is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

Homepage: https://firejail.wordpress.com

firejail(1), firemon(1), firecfg(1), firejail-login(5), firejail-users(5), https://github.com/netblue30/firejail/wiki/Creating-Profiles

Jun 2022 0.9.64.4